# AP Environmental Science : Geological Time Scale

## Example Questions

### Example Question #1 : Geological Time Scale

Geological time scales are used to measure spans of time. In terms of geological time scales, which category represents the smallest length of time?

Eon

Period

Era

Supereon

Period

Explanation:

The correct response is period. This would be the smallest measurement of time given the answer choices.

The order from longest to shortest is shown here: Supereon > Eon > Era > Period

### Example Question #2 : Geological Time Scale

Geological time scales are used to measure spans of time. In terms of geological time scales, which category represents the longest length of time?

Epoch

Age

Era

Period

Era

Explanation:

The correct response is era because it represents longer periods of time on the geological time scale. The answer choicest from longest to shortest are as follows: Era > Period > Epoch > Age.

### Example Question #3 : Geological Time Scale

Examine the given block diagram. Each letter represents a depositional event or a period of erosion. Place the letters in order from the oldest to youngest event.

E, F, D, A, B, C

C, B, A, E, D, F

E, C, B, A, D, F

F, D, E, A, B, C

C, B, A, D, F, E

C, B, A, E, D, F

Explanation:

The law of superposition states that the oldest rock layers are at the bottom. A real world example of this often takes place while cooking. When making a seven-layer dip, for instance, you place the oldest layer on the bottom of the dish and stack layers on top. The layer on top is the youngest. The earth is made of rock layers deposited in a similar way.

E represents a period of erosion, meaning there is "missing time" (rock layers have been eroded, so there are no rocks representing that time).